408 Cleveland with Sniper and Hyperspark

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Grego

Member
Joined
Oct 25, 2017
Messages
20
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Location
New Zealand
My Car
1973 March 1

[url=https://ibb.co/mPf7WR][img]https://preview.ibb.co/eghMrR/20150725_122041_resized_1.jpg[/img][/url]
HI all

Does anyone have a sniper with hyperspark set up? I have got mine running, but very poorly. Its over fueling to the point that the plugs get wet and will not start.

Its a 408 with Aussie 2V ali heads, 10:1 compression and a reasonable agressive cam.

Looking to get someones tune that they have in their Sniper as a better than the factory starting point.

THANKS

 
My guesses are either wiring is incorrect or a vacuum leak.

Did you install the Sniper immediately after the engine was installed, or did you run it for a while with a carburetor and stock ignition, if so, how did it run? Did you do anything else when you installed the Sniper, like a new intake manifold?

Make sure you have at least 12 volts to the Sniper when the engine is running.

Go through the controller setup again, step by step, do not skip any steps.

 
Grego,

Check your timimg with a timing light at idle and make sure it matches the parameters you setup in the wizard.

what is your iac reading at idle with engine at operating temperature ?

what are your idle and cruise settings in the wizard ?

Do you get to closed loop? and are you seeing idle learning and learning during cruise.

Typically one would want around 13.5 afr at idle and around 14.0 @ cruise.

if your iac numbers are over about 8 or so you will have issues transitioning from idle to cruise, your engine SHOULD be able to idle with the iac opening closed off completely off with a heavy piece of tape.

If you cannot get the iac less than 10, i would suggest you completely cover the iac opening with tape and set your idle rpm 50 rpms less than your target rpm.

Boilermaster

 
Hi all and thanks for the quick replies.

Engine is a fresh rebuild, sniper is new on the engine

Timming is confirmed at 15 deg (same as setting in sniper)

Sensors are all reading stable numbers and not jumping or showing errors.

12.8 volts to sniper, down to 10.9 while cranking and charging at 13.4 while engine running.

Idle target is 850, will idle anywhere between 750 and 1100

IAC shows 20 while engine is warming up

AFR anywhere between 12.5 and 14

Does go into learning mode once above 160 deg.

Idle timing at 15 deg and WOT 28 with 30 cruise (engine builders recommendations to run in at)

Interesting I have spoken with others that will say at idle their timing numbers will move anywhere between 8 and 15 deg as the sniper is trying to smooth the idle, mine will say at 15 all the time.

I will get it running again later in the week and do a video of the screen.

Thanks

Grego

 
Hi all and thanks for the quick replies.

Engine is a fresh rebuild, sniper is new on the engine

Timming is confirmed at 15 deg (same as setting in sniper)

Sensors are all reading stable numbers and not jumping or showing errors.

12.8 volts to sniper, down to 10.9 while cranking and charging at 13.4 while engine running.

Idle target is 850, will idle anywhere between 750 and 1100

IAC shows 20 while engine is warming up

AFR anywhere between 12.5 and 14

Does go into learning mode once above 160 deg.

Idle timing at 15 deg and WOT 28 with 30 cruise (engine builders recommendations to run in at)

Interesting I have spoken with others that will say at idle their timing numbers will move anywhere between 8 and 15 deg as the sniper is trying to smooth the idle, mine will say at 15 all the time.

I will get it running again later in the week and do a video of the screen.

Thanks

Grego
As mentioned above, you want your IAC to read between 2-10 when you above 160 degrees. If you're higher than that you want to close your blades more and recheck. Keep in mind that ever time you adjust your blades you have to reset by turning the car off and restart.

 
GREGO, iac around 20 warming up is meaningless, you need to know what it is fully warmed up in closed loop.

AFR readings the same 12.5 would be not a good situation at idle or cruise, go back on in the wizard and see what your targets are.

12.5 is great for WOT but poor choices anywhere else.

Boilermaster

 
Grego & 73'mach1, 

closing throttle blades will raise iac numbers NOT lower them.

After getting the iac where you want it and cycling the key to re zero tps one needs to make sure iac is repeatable, ask me how I know.

Boilermaster

 
Nice and lcean look, and they were cheap! I like your set up on the front of your engine, tidies up the engine bay. I am going to run mine stock for now, but I would like to do something similar in the future. You are running the GM type power steering pump, did you have to do anything else to the factory power steering?

 
Nice and lcean look, and they were cheap! I like your set up on the front of your engine, tidies up the engine bay. I am going to run mine stock for now, but I would like to do something similar in the future. You are running the GM type power steering pump, did you have to do anything else to the factory power steering?
I'm using the GM style hooked up to a hydraboost break system. 

20210610_214537.jpg

 
Hi

How is your fuel pressure ? Have you checked with a gauge ? sniper should run at 58 ? How does your timing map look like ? Should really make a map

not use the one the guide builds. Check that ECU and handheld has the latest firmware. How is the O2 sensor setup ? Take a log file from cold start.

Exahuast leak can fool the 02 sensor creating this issue, also combined with a healthy cam its getting more problematic,

 
Last edited by a moderator:
Hi Rob

Fuel is just under 60 psi while engine running. I have updated to latest firmware.

O2 sensor is about 8 inches down from my collectors at about 10 oclock facing down in a welded bung.

I will run a log.

I will also recheck for a leak, I used a tissue paper and ran it around looking for movement but did not see any, I will use a short hose and listen for one next time.

Thanks

 
Grego, 

Don C brings up a very valid point (as always).

Since this is a NEW build how we know  that your issue is not a base engine issue such as valve timing , lifter preload or distributor phasing ?

Holley does state that one should get a good base tune before letting the sniper control timing.

do you per chance have a known good carb, mechanical distributor and fuel pressure regulator ?

I know it is a stretch, but you could be looking at a very long road without knowing how your base engine stacks up, and if you have to bring it to a professional tuner, that can be pretty costly as well.

a couple things to look at would be map readings at hot idle (KPA) and convert that over to inches of vacuum and see if that corresponds to your cam card specs, cranking compression ( actual ) might be useful.

Boilermaster

 
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